Insert the 6 mm Allen wrench into the back of the spring guide at the back of the gearbox.

Push in and turn the wrench 90 degrees to release the spring guide and spring.

The spring is heavy and will require a lot of force to push in.

The goal of turning the wrench is to line up the winglets with the holes in the back of the gearbox.

The spring will want to jump out of the gearbox, so hold on to it tightly.